U.S.-GLOBEC: NEP Phase IIIb-CGOA: Habitat effects on feeding, condition, growth and survival of juvenile pink salmon in the northern Gulf of Alaska

东北太平洋引起了海洋学越来越大的兴趣，因为对鲑鱼丰度十年尺度波动的观测似乎与整个盆地的气象强迫和海洋学条件的变化有关。尽管改变生态系统结构和功能的机制还没有很好的文献记载，但这些变化表明气候变化在生物生产力中得到了迅速的表达。粉红鲑鱼特别适合作为海洋状况的指标，因为它们数量丰富，生命周期短，只有两年，而且世代不重叠。来自威廉王子湾（PWS）孵化场的粉红鲑鱼幼崽携带热耳石标记，可以估计其早期海洋阶段的生长和整体群体生存，从而为研究栖息地质量的影响提供了难得的机会。因此，该项目使用了四个项目的数据，这些数据是在果阿北部取样的幼粉鲑鱼，根据时间和栖息地来估计每个孵化场队列的摄食强度、条件和生长情况。将确定有利栖息地的发生（即幼粉鲑鱼摄食良好，条件良好，生长最快），从而描述其特征。由于体型较大的鲑鱼幼鱼的死亡率会降低，因此，由于体型较大、生长速度较快的鲑鱼的特征可能比总体平均值或中位数更能反映栖息地质量，因此，以较大的尺寸为基础的分位数确定其摄食、状况和生长情况。这种综合策略是一种自上而下的方法，因为是鱼类决定何时何地出现有利的栖息地。对气候和海洋学条件影响海洋生态系统和鲑鱼产量的过程的机制理解仍然缺乏。最优稳定性假设（OSH）表明，在果阿北部，夏季水柱稳定性的增加增加了初级生产和浮游动物的丰度；提高了幼鲑鱼的摄食、生长和存活率。研究了水柱稳定性、叶绿素深度分布、深度光有效性、浮游动物丰度和鲑鱼响应变量（摄食、条件和生长），以确定它们之间的显著相互关系及其对OSH的影响。这个项目将导致建立一个由四个项目汇编而成的粉红鲑鱼幼鱼综合数据库。本项目资助博士生1名，博士后1名。阿拉斯加渔猎部的科学家们正在为数据库提供一组数据，这些数据将从早期海洋生存的估计中受益，以改善预测。该项目与PWS鲑鱼渔业的利益相关者联盟保持着密切的互动。该小组开发了一个网站，用于将我们的综合研究结果传达给更广泛的资源依赖社区PWS和GOA北部。

The northeast Pacific Ocean is of increasing oceanographic interest as observations of decadal-scale fluctuations in salmon abundance appear linked to basin-wide changes in meteorological forcing and oceanographic conditions. These regime shifts indicate that climate changes are quickly expressed in biological productivity, although the mechanisms that alter ecosystem structure and function are not well documented. Pink salmon are particularly suited to serve as indicators of marine conditions, as they are abundant and have a short, two-year life cycle with non-overlapping generations. Juvenile pink salmon from Prince William Sound (PWS) hatcheries carry thermal otolith marks that allow estimates of both growth in their early marine phase and of overall cohort survival, thus providing an exceptional opportunity to study the effects of habitat quality. Thus project uses data from four programs that sampled juvenile pink salmon in the northern GOA to estimate feeding intensity, condition, and growth for each hatchery cohort by time and habitat. The occurrence of favorable habitats (i.e. where juvenile pink salmon were feeding well, were in good condition, and exhibited fastest growth) will be identified, allowing description of their characteristics.Since mortality of juvenile salmon is reduced in larger individuals, feeding, condition and growth is determined in upper size-based quantiles as characteristics of larger, faster-growing individuals may present better indicators of habitat quality than overall means or medians. This synthesis strategy is a top-down approach, as it is the fish that decide where and when favorable habitats occurred. Mechanistic understanding of the processes by which climate and oceanographic conditions affect marine ecosystems and salmon production is still lacking. The OptimalStability Hypothesis (OSH) suggests that, in the northern GOA, increased water column stability during summer enhances primary production and zooplankton abundance; leading to enhanced feeding, growth and survival of juvenile salmon. Water column stability, depth distribution of chlorophyll, light availability at depth, zooplankton abundance and salmon response variables (feeding, condition and growth) are examined to determine significant inter-relationships among them, and their bearing on the OSH.This project will lead to the development of a comprehensive database for pink salmon juveniles, compiled from four projects. A Ph.D. student and a post-doctoral fellow are supported by this work. Scientists at the Alaska Dept. of Fish and Game are providing a data set for the database will benefit from estimates of early marine survival to improve forecasting. The project maintains a strong interaction with an alliance of stakeholders in the PWS salmon fishery. A website developed by that group is used to communicate results of our synthesis research to the broader resource-dependent community of PWS and the northern GOA.